As shown in FIG. 1, a portion of a known switchgear assembly 10 includes a frame 12 and a draw-out assembly 16. The frame 12 defines a switchgear cell 17, and supports an array of switchgear stationary disconnects 20. The number and arrangement of stationary disconnects 20 can differ as known in the art, but in the given example the stationary disconnects 20 project vertically upward in front and rear rows 22 and 24 of three. Each row 22 and 24 of stationary disconnects 20 has an assembly of bus bars 26, also known as bus work, for connection to either a current source or load. The draw-out assembly 16 has a corresponding array of vertical disconnects 30 arranged in front and rear rows 32 and 34 of three.
The draw-out assembly 16 further includes pole units 36, one of which is shown in the view of FIG. 1, and a circuit breaker 38. Each pole unit 36 interconnects a vertical disconnect 30 in the front row 32 with another in the rear row 34. The circuit breaker 38 is operatively associated with the pole units 36 to open and close the electrical current paths between the two rows 32 and 34 of vertical disconnects 30.
The frame 12 stands on a building floor 40, and provides a cell floor 41. The draw-out assembly 16 is supported on the building floor 40 by wheels 42. In use, the draw-out assembly 16 is rolled into the cell 17 from the building floor 40 onto the cell floor 41 to a position in which the vertical disconnects 30 are aligned beneath the stationary disconnects 20. A lifting mechanism (not shown) of known construction is then actuated to lift the draw-out assembly 16 to an engaged position in which the vertical disconnects 30 project upward into the stationary disconnects 20 in operative relationship with the stationary disconnects 20. Specifically, the draw-out assembly 16 has side flanges 46, and the frame 12 includes a lift assembly 48 that is shown partially in FIG. 1. Elevator portions 50 of the lift assembly 48 are configured to receive the side flanges 46 in weight-bearing relationship for the lifting mechanism to carry the draw-out assembly 16 upward to the engaged position. The circuit breaker 38 is then engaged with the stationary disconnects 20 to control the passage of electric current between the two rows 22 and 24 of stationary disconnects 20.
When the circuit breaker 38 is to be disengaged from the stationary disconnects 20, the lifting mechanism is actuated to lower the draw-out assembly 16 from the engaged position, and thereby to withdraw the vertical disconnects 30 from the stationary disconnects 20. The draw-out assembly 16 is thus known as a vertical draw-out assembly or vertical draw-out circuit breaker assembly because it must be moved upward or downward in the vertical direction to engage or disengage the circuit breaker 38 to and from the stationary disconnects 20.